The present invention relates to a display device, and in particular, relates to a display device with a touch detection function capable of detecting an external proximity object.
In recent years, a touch detection device referred to as a touch panel capable of detecting an external proximity object has attracted attention. The touch panel is mounted on or integrated with a display device, for example, a liquid crystal display device. In a display device in which a touch panel is mounted on or integrated with a display device, that is, a display device with a touch detection function, various button images or the like are displayed on the display device, and proximity of an external object to a button image is detected through the touch panel. This enables the use of the touch panel as information input means instead of a normal mechanical button. Since such a display device with a touch detection function does not necessarily need information input means such as a keyboard or a mouse, its use tends to increase with the inclusion of mobile information terminals such as mobile phones in addition to computers.
As a detection method of a touch detection device, some methods such as an optical type, a resistance type and a capacitance type are known. Among these types, a capacitance type touch detection device has a relatively simple structure and consumes less power and so is used for mobile information terminals and the like. Japanese Patent Application Laid-Open Publication No. 2012-230657 (Patent Document 1) describes a capacitance type touch detection device.
Further, in the display device, the increase in size of a display surface has been more and more demanded. Correspondingly, the increase in size of the touch panel has also been demanded. On the other hand, the increase in size of the display device itself is not desirable because portability thereof is degraded. Thus, in order to achieve the increase in size of the display surface while suppressing the increase in size of the display device, a narrower edge frame of the display device is needed. Namely, the reduction in width of an edge frame surrounding the display surface of the display device has been demanded.